The patterns produced by the Geometric Lathe are concentric, eccentric, or geometric circles, radiating from a common centre, and beautifully interwoven into each other, forming a perfectly regular and uniform ‘fancy’ pattern, so exactly true and uniform in its radiations, that there never is the slightest possible irregularity or imperfection. It is because the patterns are of such exquisite beauty and perfection, and at the same time extremely fine and complicated, that it is utterly impossible to imitate it by hand or by any process whatever. The Geometric Lathe does not engrave the patterns immediately upon the plate itself, but the patterns are transferred to the plate from roller dies or cylinders, generally in two places, as a majority of bills contain two dies alike, sometimes four, one in each corner. Being single-transferred the patterns are reversed, and are then _white_ circles or lines upon a _black ground_. Of course whenever there are two or four dies that pretend to be alike in a genuine bill, they will all be exactly alike, being all transferred from the same one die. See the two transfers of the die in the steel plate containing the ‘3.’ In imitations of Lathe-work in counterfeit bills there will be a failure in two ways: first, in imitating regularity of the pattern, which is attempted to be done by hand, and also it is cut directly on the plate instead of transferring, so that what in the genuine is black _spaces_, is _engraved_ black in the counterfeits, leaving white spaces and black dots, resembling cobble-stones--the white spaces between which made to resemble white lines, while it can easily be seen that it is only irregular black _dots_ and scratches instead of white lines or geometric circles. Secondly, a failure in getting two dies exactly alike in the same bill--that is, where they pretend to be alike. If done by hand there cannot be two fine and complicated patterns made _exactly alike_; but in the genuine, where the pattern on one die or cylinder is rolled or transferred in two or more places, they will all of course be exactly alike. This same work is to be seen on the backs of watches, called “Engine Turning.” [Illustration: A B _Magnified 5 to 10 times._ C D _Magnified 10 to 20 times._ E F _Magnified 5 to 10 times._]